In general daily life, various lighting devices can be seen everywhere, such as fluorescent lamps, street lamps, table lamps, art lamps, and the like. In the above lighting apparatus, a tungsten filament bulb is conventionally used as a light source. In recent years, due to the rapid development of technology, light-emitting diodes (LEDs) have been used as sources of illumination. In addition, in addition to lighting equipment, for general traffic signs, billboards, lights, etc., also use LEDs as a light source. As mentioned above, the use of light-emitting diodes as light-emitting sources has the advantages of power saving and greater brightness, so it has gradually become common in use. It is well known that the quality of a power supply for which it is supplied plays an important role in the quality of the LED lamp. It is also a factor that must be carefully considered by the user and the manufacturer.